contrib/ipfilter/lib/load_http.c

   1 /* $FreeBSD$ */
   2
   3 /*
   4  * Copyright (C) 2012 by Darren Reed.
   5  *
   6  * See the IPFILTER.LICENCE file for details on licencing.
   7  *
   8  * $Id: load_http.c,v 1.5.2.5 2012/07/22 08:04:24 darren_r Exp $
   9  */
  10
  11 #include "ipf.h"
  12 #include <ctype.h>
  13
  14 /*
  15  * Because the URL can be included twice into the buffer, once as the
  16  * full path for the "GET" and once as the "Host:", the buffer it is
  17  * put in needs to be larger than 512*2 to make room for the supporting
  18  * text. Why not just use snprintf and truncate? The warning about the
  19  * URL being too long tells you something is wrong and does not fetch
  20  * any data - just truncating the URL (with snprintf, etc) and sending
  21  * that to the server is allowing an unknown and unintentioned action
  22  * to happen.
  23  */
  24 #define MAX_URL_LEN     512
  25 #define LOAD_BUFSIZE    (MAX_URL_LEN * 2 + 128)
  26
  27 /*
  28  * Format expected is one addres per line, at the start of each line.
  29  */
  30 alist_t *
  31 load_http(char *url)
  32 {
  33         int fd, len, left, port, endhdr, removed, linenum = 0;
  34         char *s, *t, *u, buffer[LOAD_BUFSIZE], *myurl;
  35         alist_t *a, *rtop, *rbot;
  36         size_t avail;
  37         int error;
  38
  39         /*
  40          * More than this would just be absurd.
  41          */
  42         if (strlen(url) > MAX_URL_LEN) {
  43                 fprintf(stderr, "load_http has a URL > %d bytes?!\n",
  44                         MAX_URL_LEN);
  45                 return NULL;
  46         }
  47
  48         fd = -1;
  49         rtop = NULL;
  50         rbot = NULL;
  51
  52         avail = sizeof(buffer);
  53         error = snprintf(buffer, avail, "GET %s HTTP/1.0\r\n", url);
  54
  55         /*
  56          * error is always less then avail due to the constraint on
  57          * the url length above.
  58          */
  59         avail -= error;
  60
  61         myurl = strdup(url);
  62         if (myurl == NULL)
  63                 goto done;
  64
  65         s = myurl + 7;                  /* http:// */
  66         t = strchr(s, '/');
  67         if (t == NULL) {
  68                 fprintf(stderr, "load_http has a malformed URL '%s'\n", url);
  69                 free(myurl);
  70                 return NULL;
  71         }
  72         *t++ = '\0';
  73
  74         /*
  75          * 10 is the length of 'Host: \r\n\r\n' below.
  76          */
  77         if (strlen(s) + strlen(buffer) + 10 > sizeof(buffer)) {
  78                 fprintf(stderr, "load_http has a malformed URL '%s'\n", url);
  79                 free(myurl);
  80                 return NULL;
  81         }
  82
  83         u = strchr(s, '@');
  84         if (u != NULL)
  85                 s = u + 1;              /* AUTH */
  86
  87         error = snprintf(buffer + strlen(buffer), avail, "Host: %s\r\n\r\n", s);
  88         if (error >= avail) {
  89                 fprintf(stderr, "URL is too large: %s\n", url);
  90                 goto done;
  91         }
  92
  93         u = strchr(s, ':');
  94         if (u != NULL) {
  95                 *u++ = '\0';
  96                 port = atoi(u);
  97                 if (port < 0 || port > 65535)
  98                         goto done;
  99         } else {
 100                 port = 80;
 101         }
 102
 103
 104         fd = connecttcp(s, port);
 105         if (fd == -1)
 106                 goto done;
 107
 108
 109         len = strlen(buffer);
 110         if (write(fd, buffer, len) != len)
 111                 goto done;
 112
 113         s = buffer;
 114         endhdr = 0;
 115         left = sizeof(buffer) - 1;
 116
 117         while ((len = read(fd, s, left)) > 0) {
 118                 s[len] = '\0';
 119                 left -= len;
 120                 s += len;
 121
 122                 if (endhdr >= 0) {
 123                         if (endhdr == 0) {
 124                                 t = strchr(buffer, ' ');
 125                                 if (t == NULL)
 126                                         continue;
 127                                 t++;
 128                                 if (*t != '2')
 129                                         break;
 130                         }
 131
 132                         u = buffer;
 133                         while ((t = strchr(u, '\r')) != NULL) {
 134                                 if (t == u) {
 135                                         if (*(t + 1) == '\n') {
 136                                                 u = t + 2;
 137                                                 endhdr = -1;
 138                                                 break;
 139                                         } else
 140                                                 t++;
 141                                 } else if (*(t + 1) == '\n') {
 142                                         endhdr++;
 143                                         u = t + 2;
 144                                 } else
 145                                         u = t + 1;
 146                         }
 147                         if (endhdr >= 0)
 148                                 continue;
 149                         removed = (u - buffer) + 1;
 150                         memmove(buffer, u, (sizeof(buffer) - left) - removed);
 151                         s -= removed;
 152                         left += removed;
 153                 }
 154
 155                 do {
 156                         t = strchr(buffer, '\n');
 157                         if (t == NULL)
 158                                 break;
 159
 160                         linenum++;
 161                         *t = '\0';
 162
 163                         /*
 164                          * Remove comment and continue to the next line if
 165                          * the comment is at the start of the line.
 166                          */
 167                         u = strchr(buffer, '#');
 168                         if (u != NULL) {
 169                                 *u = '\0';
 170                                 if (u == buffer)
 171                                         continue;
 172                         }
 173
 174                         /*
 175                          * Trim off tailing white spaces, will include \r
 176                          */
 177                         for (u = t - 1; (u >= buffer) && ISSPACE(*u); u--)
 178                                 *u = '\0';
 179
 180                         a = alist_new(AF_UNSPEC, buffer);
 181                         if (a != NULL) {
 182                                 if (rbot != NULL)
 183                                         rbot->al_next = a;
 184                                 else
 185                                         rtop = a;
 186                                 rbot = a;
 187                         } else {
 188                                 fprintf(stderr,
 189                                         "%s:%d unrecognised content:%s\n",
 190                                         url, linenum, buffer);
 191                         }
 192
 193                         t++;
 194                         removed = t - buffer;
 195                         memmove(buffer, t, sizeof(buffer) - left - removed);
 196                         s -= removed;
 197                         left += removed;
 198
 199                 } while (1);
 200         }
 201
 202 done:
 203         if (myurl != NULL)
 204                 free(myurl);
 205         if (fd != -1)
 206                 close(fd);
 207         return rtop;
 208 }